GB1568307A

GB1568307A - Additional charge of a diesel internal-combustion engine

Info

Publication number: GB1568307A
Application number: GB29642/77A
Authority: GB
Original assignee: MTU Friedrichshafen GmbH; MTU Motoren und Turbinen Union Friedrichshafen GmbH
Current assignee: Rolls Royce Solutions GmbH
Priority date: 1976-07-16
Filing date: 1977-07-14
Publication date: 1980-05-29
Also published as: JPS5311221A; CH623382A5; US4162668A; DE2632015A1; FR2358562A1; FR2358562B1; ES460780A1; IT1078885B

Description

PATENT SPECIFICATION

( 11) 1568307 Application No 29642/77 ( 22) Filed 14 July 1977 Convention Application No 2 632 015 Filed 16 July 1976 in Fed Rep of Germany (DE)

Complete Specification rpublished 29 May 1980

TNT CL ' F 02 B 29/00 t 19) Index at acceptance FIB 2 M 1 2 N 14 A 2 N 16 A 2 N 1 2 P 4 2 P 5 B 122 B 228 B 300 BA FIK 2 F 6 A 1 2 F 6 G 3 2 F 6 H 1 ( 54) ADDITIONAL CHARGE OF A DIESEL INTERNAL-COMBUSTION ENGINE ( 71) We, MOTOREN UND TURBINENUNION FRIEDRICHSHAFEN Gmb H, a West German Body Corporate, of D-7990 Friedichshafen,1, Olgastrasse 75, P'ostfach 289, Federal Republic of Germany do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:-

The invention relates to a multicylinder diesel internal-combustion engine comprising cylinders with inlet and outlet valves, and coripressed air starting means comprising a starting reservoir an additional valve for each cylinder and a control device with which at least a part of the additional valves is controlled in starting during the working stroke of the associated cylinder and the starting-air thereby admitted into the associated cylinder In German patent specification No 2221567 a control device for a supercharged diesel internal-combustion engine is described, in which the supply of starting air for improving the acceleration of the engine and/or reducing the drop in rotational speed, upon sudden lead take-up of the engine operating with fuel, is effected even in the region of over 50 % of the fullload rotational speed.

The intended effect of this known control device, i e to compensate in an acceleration operation or during sudden load take-up for the supercharge air of the exhaust-driven turbocharger lacking during these operating conditions by supplying compressed air from the starting-air reservoir, can be achieved only partially, since the supply of compressed air is effected by the control valve during the respective working stroke and the fresh air admitted thereby is discharged into open air during subsequent exhausting of the burnt gases, so that the majority of the fresh air cannot take part in the combustion process Moreover, after a starting procedure, the pressure level in the starting-air reservoir is considerably lowered by the air consumption during starting Accordingly, the maximum possible air pressure is not available for the acceleration stage from idling rpm to full-load rpm, which is normally necessary immediately thereafter In this way the primary action of the compressed air on the piston is reduced and the supply of c 6 mpressed air at the end of the working stroke takes place only at a later point in time when the combustion pressure has dropped correspondingly In this way the amount of air admitted and its effect on the temperature level in the cylinder is reduced.

The invention provides a multicylinder diesel internal-combustion engine comprising cylinders with inlet and outlet valves, and compressed air starting means comprising a starting-air reservoir, an additional valve for each cylinder and a control device with which at least some of the additional valves is controlled in starting during the working stroke of the associated cylinder and the starting-air thereby admitted into' the associdated cylinder, wherein the engine'has a further air reservoir which, in order to avoid a drop in rotational speed during suddenload or for better acceleration of the internal-combustion engine, supplies compressed air to preferably all the cylinders of the internal-combustion engine via the additional valves, these valves being controlled by a further control device so that the compressed air enters each cylinder during the induction stroke and in the first third of the compression stroke.

By way of example one embodiment of a multicylinder diesel internal-combustion engine according to the invention will now be described with reference to the accompanying drawing.

A six-cylinder diesel internal-combustion engine 11 having an exhaust-driven turbocharger (not shown) is provided with a compressed-air starting unit which comprises a starting-air reservoir 12, air-inlet valves 13 to 15 and a starting-air distributor 16 By way of a solenoid valve 17 actuated upon m ( 21) ( 31) ( 32) ( 33) ( 44) ( 51) ( 52) supercharging of the diesel engine As soon as the speed of rotation of the diesel engine drops below the given value, on account of a sudden load, the additional compressed 65 air supply is reconnected In this way the rotational speed of the engine is prevented from dropping excessively and the rated rotational speed can be rapidly reached once more 70 The two air reservoirs 12 and 30 are replenished during the running of the diesel internal-combustion engine or are maintained at its rated pressure, so that sufficient air at adequate pressure is available for the next 75 starting and acceleration operations.

The advantage of this embodiment is that, as a result of providing an additional separate air reservoir, the full air pressure is available to replace the deficient super 80 charging air, even directly after a starting operation By the provision of the second control distributor it is possible for the additional compressed air to be admitted into the cylinders when the normal inlet 85 valve is open, i e during the induction stroke and in the first third of the compression stroke In this case the quantity of additional air is so determined that the deficient amount of air charge is fully compensated 90 thereby during an acceleration stage or during sudden loading.

These measures make it possible to achieve an effective shortening of the running-up time of the diesel engine from the lowest rpm 95 until reaching its rated rpm and a considerable reduction in the drop in rpm upon sudden load take-up of the running engine.

Claims

WHAT WE CLAIM IS: -

1 A multicylinder diesel internal-comn 100 bustion engine comprising cylinders with inlet and outlet valves, and compressed air starting means comprising a starting-air reservoir, an additional valve for each cylinder and a control device with which at least some 105 of the additional valves is controlled in starting during the working stroke of the associated cylinder and the starting-air thereby admitted into the associated cylinder, wherein the engine has a further air reser 110 voir which, in order to avoid a drop in rotational speed during sudden-load or for better acceleration of the internal-combustion engine, supplies compressed air to preferably all the cylinders of the internal-combustion 115 engine via the additional valves, these valves being controlled by a further control device so that the compressed air enters each cylinder during the induction stroke and in the first third of the compression stroke 120

2 A multicylinder diesel internal-combustion engine substantially as hereinbefore starting the internal-combustion engine, compressed air from the starting-air reservoir 12 passes along a pipe 18, through a non-return valve 19 and a pipe 20 to reach the air-inlet valves 13 to 15 and through a pipe 21 to reach the starting-air distributor 16 which is driven by the internal-combustion engine and which distributes the compressed air as control air through a second solenoid valve 22 and along pipes 23, 24, and pipes 26, 27,

28 to the air-inlet valves 13 15 In this way the compressed air present in the pipe 20 is injected during the working stroke of the corresponding cylinder and can act on the piston in order to start up the internal-combustion engine.

In accordance with this embodiment of the invention, a further air reservoir 30 and a further air-control distributor 31 are provided which admit compressed air into the cylinders, during the acceleration and sudden-load phases of the internal-combustion engine when the normal inlet valve is open, i.e during the induction stroke and in the first third of the compression stroke, through the air-inlet valves 13 to 15 and through further air-inlet valves 32 to 34 Accordingly the compressed air from the air reservoir 30 passes via a pipe 35, via a solenoid valve 36 to be actuated, via a non-return valve 37 and via pipes 20 and 38 to reach the air-inlet valves 13 to 15 and 32 to 34 Also the compressed air from the air reservoir 30 passes via a pipe 39 to reach the air-control distributor 31 which is likewise driven by the internal-combustion engine and which distributes compressed air as control air through the solenoid valve 22 to be actuated and through pipes 40 45, 26 28, 46 48 to the air-inlet valves 13 15 and 32 34.

The control takes place in such a way that until reaching the starting rotational speed of about 100 to 150 rpm by actuation of the solenoid valve 17 the compressed air is taken from the starting-air reservoir 12 and is injected in during the working stroke of at least some of the cylinders Above this speed of rotation the solanoid valve 17 is de-ener gized and by actuation of the solenoid valves 22 and 36 the running-up of the diesel engine is effectively assisted by injecting compressed air from the additional air reservoir 30 during the induction stroke and compression stroke of preferably all cylinders Upon reaching a given speed of rotation which can be set and which is slightly below the rated rotational speed, the flow of additional compressed air is interrupted by de-energizing the solenoid valves 22 and 36 At this 'rotational speed the exhaust-driven turbocharger is capable of completely taking over the 1,568,307 1,568,307 described with reference to and as shown in the accompanying drawing.

3 A vehicle having a multicylinder diesel internal-combustion engine as claimed S in claim 1 or claim 2.

MOTOREN-UND-TURBINEN-UNION, FRIEDRICHSHAFEN Gmb H, Per: BOULT, WADE & TE Nq NAN Tr, 34 Cursitor Street, London EC 4 A 1 PQ, Chartered Patent Agents.

Printed for Her Majesty's Stationery Office by Burgess & Son (Abingdon), Ltd -1980.

Published at The Patent Office, 25 Southampton Blildings, London, WC 2 A l AY, from which copies may be obtained.